Railroad track rails are subject to wear by the passage of trains over the rails. In particular, depressions in the upper surface of a rail may develop such that the rail head presents an undulating, corrugated surface. Moreover, the rail may develop burrs, or otherwise lose its symmetrical profile. Maintenance of smooth running surfaces on railroad track rails is important for reasons of safety, riding comfort, protection of the track, track bed and rolling stock, noise suppression, and reduced maintenance of the track and track bed.
Grinding machines for maintaining railroad track rails in smooth, properly shaped condition are known. Such grinding machines generally comprise a plurality of rotatable grinding modules carried, by a locomotive or the like, in close proximity to the rail head surfaces of a railroad track. The grinding modules include rotatable, abrasive grinding stones that can be lowered into a position flush with the rail surface to grind and restore the rail surface to a smooth, planar configuration.
Shaping of a rail can be accomplished by tilting the grinding module, and in particular the grinding stone, relative to the level upper surface of the railroad track rail. Examples of rail grinding machines having tiltable grinding modules include U.S. Pat. No. 4,178,724 to Bruno, U.S. Pat. No. 3,707,808 to Danko et al., U.S. Pat. No. 3,606,705 to Rivorire, U.S. Pat. No. 2,197,729 to Miller, and U.S. Pat. No. 2,132,470 to Hobson et al. The angle through which such grinding modules can be tilted, however, is restricted by the inherent size of the grinding modules, and the space limitations imposed on all railroad rolling stock due to the relatively narrow width between track rails. Such limitations have, heretofore, restricted the tilt angle of grinding modules as measured from a center reference axis. As will be appreciated, the shaping capabililty of an individual grinding module is limited by the maximum tilt angle of the grinding module.